The present invention relates to a process for continuous manufacture of esters, or in particular of acetates, by a catalytic transesterification reaction in a homogeneous liquid phase.
British patent application GB-2 017 083 describes a process for the manufacture of ethylmonoglycol ether acetate by a catalytic transesterification reaction using ethyl acetate and ethylmonoglycol ether. The reaction is carried out in a heterogeneous phase in the presence of a catalyst consisting of a solid ion exchange resin at a relatively low temperature, lower than 100.degree. C.
U.S. Pat. No. 3,700,726 discloses a process for the manufacture of (poly)ethylene glycol ether acetate by a catalytic transesterification reaction using an alkyl acetate with a (poly)ethylene glycol ether in the presence of a catalyst chosen from metal alcoholates. During the reaction only one alcohol is used, which is a (poly)ethylene glycol ether.
U.S. Pat. No. 4,370,491 and French patent FR-2 611 704 disclose processes for the manufacture of acetate by a catalytic transesterification reaction using an acetate and an alcohol in the presence of a catalyst chosen from metal alcoholates.
It has been noticed that an industrial unit continuously manufacturing esters, or in particular acetates, according to the processes as described above must be stopped for several days each time that the type of ester to be manufactured is changed. It has been observed that, in general, such an industrial unit can thus be stopped for one or two months a year, which corresponds to considerable losses of output.
Furthermore, search is continuing for processes which enable esters, or in particular acetates, to be manufactured with a high degree of purity, that is to say containing very few by-products.